Measuring Drum brakes
 

Just making absolutely sure, it may be a dumb question, but I didn't see it addressed in the main forum. . .

(In my 68 Dodge Coronet)

When measuring drum brakes, I'm Measuring the inside diameter of the drum, and the width of the brake pad, so I came up with 10" by 2 1/2 inches exactly, which tells me which drums to order. Is this the right measurement? Found some drums at Rock Auto for under $50 and I want to order them, but I don't want to pay for shipping on heavy drums to return them if they're wrong.

So yeah, just making sure I'm taking the right measurement in the first place.

These are the drums I'm looking at : https://i.imgur.com/C7qIu.png

Thanks all!

10x2.5 is the most common size of drum used on almost everything except early A body's. My personal preference is to use the finned HD drums, used on station wagons and some vans

Thanks. . . . I'm gonna convert the front end to disc soon, gonna leave the back on drums until I have some more $$$ to spend. So I'll probably buy some cheapies like the ones above, unless I can JunkYard some finned ones.

Disk conversion for the front is a 100% improvement in braking. Rear drums
work just fine !!! No real need to put disks on the rear.. A lot of the F body wagons used the finned drums if looking at junk yards, All rear drive cars (check the size) I have always been hard on brakes finned drums handle the heat better.

Hmm, in that case, maybe I'll just do a thorough rebuild of the drum rear brakes. It would look nice too. I'll also look for the better finned drums.

Thanks for the heads up. Down the road I will likely go to disc just for the hell of it, but right now she just needs to stop!

Oh, and, am I measuring the right thing then? For the 2.5 inch measurememnt, that was the width of the pad. . . I didnt really see a way to accurately measure the inside width of my drum. . . .

Yes, pad width is correct. This does not apply to any common (US) passenger cars I can think of, but not ALL drums are "even" sizes, 11", 11 1/2", etc. There were some that fit some pickups (Ford?) that were some 11" some od ?/32 size NEW I believe

Also be careful of used drums. It used to be VERY common for guys to pay way too much money for used drums that were "at" or very near the throwaway figure. You can only turn passenger drums, generally .060" oversize

Awesome.

Thanks, I'll probably just go with the new ones then.

Really really appreciate all the info.

Build sheet question
 

My Build Sheet has "B31" in the Brake area. Does this mean 11 inch brakes?